The immune system protects human body from bacterial, parasitic, fungal, viral infections and from the growth of tumor cells. Immunity can be classified as innate immunity or as adaptive immunity. Innate immune responses typically occur immediately upon infection for providing of an early barrier to infectious disease whereas adaptive immune responses occur later with the generation of antigen-specific long term protective immunity.
However, the immune response can sometimes be unwanted and cause immune-mediated disorder. The disorder includes autoimmune disease, graft rejection, hypersensitivity, diseases associated with the over-stimulation of host's immune system by microbes and Toll-like receptor (TLR)-mediated disease. The autoimmune diseases results from an adaptive immune response or innate immune response or both against endogenous and/or exogenous antigens. Foreign substances, derived from bacteria, parasites, fungi or viruses, may mimic self-proteins and stimulate the immune system to launch responses to a self-cell and tissue, resulting in the diseases including but not limited to systemic lupus erythematosus (SLE) and rheumatoid arthritis. The graft rejection is a consequence of organ or tissue transplantation caused by the immune response in the transplant recipient (host) to the transplanted organ/tissue. When a subject is transplanted with grafts including kidney, pancreas, heart, lung, bone marrow, cornea and skin, the subject can launch an immune response (rejection) against the grafts. Hypersensitivity is an inappropriate immune response that has deleterious effects, resulting in significant tissue damage or even death. The hypersensitivity is divided into four types (e.g. Types I, II, III and IV. Disease associated with the over-stimulation of host's immune system by microbes is triggered by the infection of viruses such as flu viruses and other microbes. In the case of flu virus and Gram-negative bacterial infection, an excessive immune response to the invaders appears to be a fatal factor in patients. The response is characterized by the overproduction of cytokines. Studies of septic shock syndrome demonstrate that over production/aberrant production of cytokines can lead to rapid mortality due to cytokine-mediated lethal shock (Slifka M K, et al. J Mol Med. 2000; 78(2):74-80). Septic shock following gram-negative infection is a leading cause of mortality in critically ill patients. The exaggerated production of cytokines is known to contribute to sepsis characterized by cytokine-mediated lethal shock (Espat N J, et al. J Surg Res. 1995 July; 59 (1):153-8). Multiple organ dysfunction syndromes (MODS) are a major cause of morbidity and mortality in severe sepsis and shock. Cytokine-mediated lethal shock resulted from over-production of host cytokines is considered a main mechanism leading to MODS (Wang H, et al. Am J Emerg Med. 2008 July; 26 (6):711-5). Toll-like receptor (TLR)-mediated disease is a disorder caused by the activation of Toll like receptors (TLRs).
TLRs are a family of receptors that recognize microbe derived molecular structures (pathogen-associated molecular patterns or PAMPs). TLR expressing immune cells are activated upon binding of PAMPs. TLRs recognize a range of pathogen-derived products and activated. Lipopolysaccharide (LPS) of bacteria recognized by TLR4, lipotechoic acid and diacylated lipopeptides by TLR2-TLR6 dimmer, triacylated lipopeptides by TLR2-TLR1 dimmer, CpG containing oligonucleotide (CpG ODN) synthesized or derived from either viruses or bacteria by TLR9, bacterial flagellin by TLR5, zymosan by TLR2-TLR6 dimmer, F protein from respiratory syncytial virus (RSV) by TLR4, viral-derived double-stranded RNA (dsRNA) and poly I:C, a synthetic analog of dsRNA by TLR3; viral DNA by TLR9, single-stranded viral RNA (VSV and flu virus) and synthetic guanosine analogs such as imidazoquinolines and imiquimod by TLR7 and TLR8 (Foo Y. Liew, et al. Nature Reviews Immunology. Vol 5, June 2005, 446-458).
In recent years, TLR activation has been connected to the pathogenesis of some of diseases including sepsis, dilated cardiomyopathy, diabetes, experimental autoimmune encephalomyelitis, systemic lupus erythematosus, atherosclerosis, asthma, chronic obstructive pulmonary disease and organ failure (Foo Y. Liew, et al. Nature Review Immunology, Vol 5, 2005, 446-458). Activation of TLR9 by self DNA play an important role in the development of autoimmune diseases such as psoriasis (Gilliet M, et al. Nat. Rev. Immunol. 2008, 594-606), SLE (Christensen S R, et al. Immunity 2006; 25:417-28; Barrat F J, et al. J Exp Med 2005; 202:1131-9; Wellmann U, et al. Proc Natl Acad Sci USA 2005; 102:9258-63) and rheumatoid arthritis (Leadbetter E A, et al. Nature 2002; 416:603-7; Boule M W, et al. J Exp Med 2004; 199:1631-40).
It has been documented that TLR9 agonist activates both innate and adaptive immune response (Arthur M. Krieg. Nature Reviews Drug Discovery, Vol 5. June 2006, 471-484). It was documented an oligonucleotide with a nucleotide sequence of 5′-cctcctcctcctcctcctcctcct-3′ prevented proliferation of human peripheral blood mononuclear cells (PBMCs) and production of IFNs, which induced by TLR9 agonists (US8030289B2).
The references cited herein are not admitted to be prior art to the claimed invention.